Field of the Invention
This invention relates to invasive medical devices. More particularly, this invention relates to ablation of tissue using such devices.
2. Description of the Related Art
Ablation of body tissue using electrical energy is known in the art. The ablation is typically performed by applying alternating currents, for example radiofrequency energy, to electrodes, at a sufficient power to destroy target tissue. Typically, the electrodes are mounted on the distal tip of a catheter, which is inserted into a subject. The distal tip may be tracked in a number of different ways known in the art, for example by measuring magnetic fields generated at the distal tip by coils external to the subject. The catheter may be provided with unipolar or bipolar ablation electrodes.
Kratoska, U.S. Patent Application Publication No. 20080275440 is directed to a method of providing feedback regarding the outcome of ablation therapy. A method is provided for obtaining feedback regarding the results of tissue ablation, the method comprising deploying one or more needles from a catheter into a target tissue, delivering energy via at least one of the one or more needles to ablate at least a portion of the target tissue to form a lesion, stopping energy delivery via the at least one of the one or more needles, and measuring a tissue property via at least one of the one or more needles after the energy delivery has been stopped. The measured tissue property may be temperature or impedance. Also, the measured tissue property may be used to determine a volume of the lesion formed by ablation therapy.